Vitamin B₁₂, generally costs between $2 and $44 depending on dosage form, manufacturer, distributor, etc. Vitamin B₁₂, the name of the Western medicine. Commonly used dosage forms are injection specifications for 1ml: 0.5mg/branch, tablets for 25μg/tablet, eye drops for 10ml: 2mg/bottle, for vitamin drugs. This product is used in megaloblastic anemia, subacute combined degenerative neurological lesions such as neuritis adjuvant therapy. The price varies with different dosage forms, manufacturers and distributors. It is recommended to purchase from local regular pharmaceutical organizations. Adverse reactions are: injection can occasionally cause rash, itching, diarrhea and allergic asthma; tablets have hypokalemia and hyperuricemia and other adverse reactions have been reported; eye drops adverse reactions are rare, and allergic reactions are occasionally seen. This product is contraindicated in known allergy to vitamin B₁₂ or previously occurred due to ophthalmic drugs causing allergic symptoms such as eye congestion, itching, swelling, rash. Use with caution in patients with glaucoma. Patients should be under the guidance of a doctor, after diagnosis of the disease to prevent the occurrence of allergic reactions or other uncomfortable symptoms. During the use of the drug, pay attention to rest, maintain adequate sleep, improve body resistance, the emergence of uncomfortable symptoms, consult a doctor in a timely manner.